X-shaped hollow α-FeOOH penetration twins and their conversion to α-Fe2O3 nanocrystals bound by high-index facets with enhanced photocatalytic activity

Nonspherical hollow nanoparticles (NHNPs) have attracted a great deal of attention in recent years due to their unique properties and many promising applications. However, compared to hollow spheres, the fabrication of NHNPs is generally much more difficult and there are only a few successful examples to date. In this work, X-shaped hollow α-FeOOH penetration twins were first synthesized by a facile hydrothermal reaction. X-shaped α-Fe2O3 hollow nanostructures with high-index {112¯3} facets exposed were further obtained via the topotactic transformation of α-FeOOH precursor. To the best of our knowledge, this is the first report on the nanostructures with high-index facets as well as a hollow interior. Owing to the special hollow structure and the high-energy surface, the as-obtained α-Fe2O3 nanocrystals show excellent visible-light photocatalytic activity toward the degradation of RhB.